Reduction of Drill Wander in Electrochemical Drilling Processes through Magnetic Alignment

<p dir="ltr">Shaped tube electrochemical machining (STEM) is one of the most reliable methods of drilling long holes in hard to machine materials. Drill wander has always been a problem in STEM since drilling tools tend to deviate more from their trajectory as the hole length increases. In order to reduce drill wander it is common in the literature to use precision manufactured titanium hollow cylindrical rods. In this work a novel non contact magnetic alignment system for STEM will be presented. This approach involves changing the structure of regular STEM tools to integrate magnets in the tool body and utilizing another magnet to align the tool magnet from outside of the rod shaped workpiece. The stiffness increase that this magnetic alignment system provides to the drilling tool as well as how to increase this stiffness value is provided through an integrated finite element analysis and a beam model. Configurations and magnet geometries that can provide increase in tool tip stiffness by an order of magnitude (or more) are presented. The effect of the alignment system on drill wander is also shown experimentally by comparing the hole structures created by the same tools while under the effect of magnetic alignment and while not. The developed alignment system successfully reduced the drill wander by around; 80\%. The robustness of the alignment system was also shown by using it under different machining voltages.</p>